CX have let the Middle Eastern carriers get a foothold in & have relied on BA to ship their pax to LHR to help fill their now 5 rotations.
If freight is struggling so much, would it not make it more viable / sense to operate a a pax aircraft ? A decent freight load on a pax aircraft would negate the need for a half empty B744F & stem the loss of pax to other operators, without impacting on their LHR ops.
But like others have said, they (CX) appear to have little interest north of London & I doubt the A350 will have any impact on that thought. I assume the B744Fs only appear here because they can't get enough slots in LHR.